So I used to be an engineer by profession and I'm prone to analyze things. I decided to do a test of actual flight time using Litchi to fly a long mission that in reality was a limited area in case something went wrong.
This morning was perfect - winds generally from the southwest about 5-6 mph. I had a mission that essentially zig-zagged back and forth over a city block at a nearby school. The entire "course" was 7 miles and rated for 23 minutes flying at the cruising speed of 25 mph. I used curves since I know Litchi pauses at each waypoint using straight lines.
So two surprises:
1 - the speed slows down considerably when curving back - the bird slows coming into the curve (almost if not zero mph) and accelerates out of it.
2 - I did not change orientation of the bird rather just left it pointing north. The surprise here was that flying backwards slowed the bird by 10 mph. That's a lot.
So pertaining to #2. I would say that the wind had something to do with it but the wind varied and was actually at a 45 angle to the direction of travel and was nowhere near 10 mph. I noticed that the RPM's stayed fairly constant on the motors varying only when slowing and accelerating out of turns.
It would seem from observation that the speed setting is just an RPM setting and does not account for any actual ground speed - no feedback from the flight system in other words. In practical terms this means that on missions your bird cannot compensate for wind speeds. The wind did not appear to add any "tailwind" effect since it flew forward at the set speed.
I can only conclude that flying in reverse has a different "tilt" to the craft causing it to "bite" less and slows the craft down.
BTW: The thing dang near made the entire circuit - it executed an RTH at the 15% level that I have set. It lacked only the last 5 rows on the pattern shown. That translates to 5.5 miles with half going 25mph and half at only 14-15 mph. I guess the moral of the story is always face forward when flying.
I'd *love* to have others weigh in on this.
This morning was perfect - winds generally from the southwest about 5-6 mph. I had a mission that essentially zig-zagged back and forth over a city block at a nearby school. The entire "course" was 7 miles and rated for 23 minutes flying at the cruising speed of 25 mph. I used curves since I know Litchi pauses at each waypoint using straight lines.
So two surprises:
1 - the speed slows down considerably when curving back - the bird slows coming into the curve (almost if not zero mph) and accelerates out of it.
2 - I did not change orientation of the bird rather just left it pointing north. The surprise here was that flying backwards slowed the bird by 10 mph. That's a lot.
So pertaining to #2. I would say that the wind had something to do with it but the wind varied and was actually at a 45 angle to the direction of travel and was nowhere near 10 mph. I noticed that the RPM's stayed fairly constant on the motors varying only when slowing and accelerating out of turns.
It would seem from observation that the speed setting is just an RPM setting and does not account for any actual ground speed - no feedback from the flight system in other words. In practical terms this means that on missions your bird cannot compensate for wind speeds. The wind did not appear to add any "tailwind" effect since it flew forward at the set speed.
I can only conclude that flying in reverse has a different "tilt" to the craft causing it to "bite" less and slows the craft down.
BTW: The thing dang near made the entire circuit - it executed an RTH at the 15% level that I have set. It lacked only the last 5 rows on the pattern shown. That translates to 5.5 miles with half going 25mph and half at only 14-15 mph. I guess the moral of the story is always face forward when flying.
I'd *love* to have others weigh in on this.
